Roles of Lipids in Photosynthesis

Abstract

Thylakoid membranes in cyanobacterial cells and chloroplasts of algae and higher plants are the sites of oxygenic photosynthesis. The lipid composition of the thylakoid membrane is unique and highly conserved among oxygenic photosynthetic organisms. Major lipids in thylakoid membranes are glycolipids, monogalactosyldiacylglycerol, digalactosyldiacylglycerol and sulfoquinovosyldiacylglycerol, and the phospholipid, phosphatidylglycerol. The identification of almost all genes involved in the biosynthesis of each lipid class over the past decade has allowed the generation and isolation of mutants of various photosynthetic organisms incapable of synthesizing specific lipids. Numerous studies using such mutants have revealed that these lipids play important roles not only in the formation of the lipid bilayers of thylakoid membranes but also in the folding and assembly of the protein subunits in photosynthetic complexes. In addition to the studies with the mutants, recent X-ray crystallography studies of photosynthetic complexes in thylakoid membranes have also provided critical information on the association of lipids with photosynthetic complexes and their activities. In this chapter, we summarize our current understanding about the structural and functional involvement of thylakoid lipids in oxygenic photosynthesis.

Relationship Between Glycerolipids and Photosynthetic Components During Recovery of Thylakoid Membranes From Nitrogen Starvation-Induced Attenuation in Synechocystis sp. PCC 6803

“…Whereas the increase in glycolipid (MGDG, DGDG and SQDG) content was gradual, that in PG content was rapid particularly between 9 and 24 h after N addition. This observation is consistent with the special importance of PG for the structure and function of photosystems (Kobayashi et al, 2016). Unlike glycolipids that are mostly used to form the lipid bilayer of thylakoid membranes, a large proportion of PG is allocated to photosystem complexes as a structural component (Kobayashi et al, 2017).…”

“…These glycerolipids form a lipid bilayer of the thylakoid membrane, which avoids free diffusion of ions and allows for generating an electrochemical potential difference across the membrane for ATP synthesis. Besides providing a matrix embedded with protein-pigment complexes and ATP synthase, glycerolipids in thylakoids play essential roles in photosynthesis as structural and functional components of PSII, cytochrome b 6 f and PSI (Kobayashi et al, 2016). Thus, biogenesis of the thylakoid membrane with the functional photosynthetic machinery needs coordinated synthesis and assembly of proteins, cofactors including Chls, and glycerolipids, as represented by essential roles of galactolipids in the thylakoid membrane organization during chloroplast development in Arabidopsis thaliana (Fujii et al, 2019b).…”

Phosphorus and nitrogen starvation reveal life‐cycle specific responses in the metabolome of Emiliania huxleyi (Haptophyta)

“…The diploid E. huxleyi stage also had a slightly higher concentration of polar lipids under nutrient‐replete conditions, especially concerning the fatty acids C 18:1n9cis , C 18:2n6cis , C 18:4n3 , C 22:0 , and C 22:6n3 , indicating differences in membrane composition. The higher abundance of polyunsaturated fatty acids could reflect differences in thylakoid membrane composition (Fulton et al ), which has been shown for haploid and diploid E. huxleyi strains before (Bell and Pond ; Fiorini et al ; Hunter et al ), and could influence photosynthetic efficiency (Kobayashi et al ). As mentioned above, differences in polar lipid composition could be attributed to diploid‐specific compartments such as vesicles for calcium carbonate pre‐concentration (Sviben et al ), and coccolith vesicle structures (Sawada and Shiraiwa ; Eltgroth et al ), or viral susceptibility (Hunter et al ).…”

Species-specific roles of sulfolipid metabolism in acclimation of photosynthetic microbes to sulfur-starvation stress

“…Mutants impaired in lipid metabolism in cyanobacteria or chloroplasts of plants have thus far been examined as to their impact on the structural and functional integrity of the oxygenic photosynthetic apparatus, whereby, the correlation of lipids, i.e., the final products of the lipid synthesis pathways, to photosynthesis has been discussed (reviewed in, e.g., [31]). Such studies include those concerning SQDG- and/or PG-deficient mutants of Synechocystis or C .…”